Tape applicators are being use to apply adhesive tape to seal a case or carton in a carton sealer machine using a conveyor to advance the carton through the machine for top and bottom tape application. The tape applicator is usually removable in and out of the machine to facilitate tape replenishing and servicing. A conventional tape applicator comprises of a main frame with tape application mechanism, tape cutting mechanism and a tape roll mounting arm with a retaining hub to secure the tape roll. The axis of rotation of the tape roll is parallel to that of the application roller which is also parallel to the surface of the carton to be taped.
The above mentioned in-line tape-roll tape applicator reduces any tape misalignment issues and provides even tension while dispensing the tape from the tape roll for normal tape application i.e.: top and bottom providing horizontal surfaces to be taped. The problem arises when taping a carton on vertical taping surfaces. The tape applicator has to be positioned horizontally to apply tape on the vertical surface.
A basic adhesive tape normally is comprised of plastic (Bi-oriented polypropylene (BOPP)) film, one side with release layer and the opposite side with adhesive layer, the adhesive is always maintain in a fluidic state which is not stable. The shape of the tape roll may change due to winding tension during manufacturing, storage and application temperature, etc., and most importantly the positioning of the tape roll during application. If the tape roll is mounted onto the tape applicator oriented horizontally i.e. with the axis of rotation of the tape roll vertical, a mild warm temperature will likely cause the tape roll to shack down-ward adjacent to its periphery and form a conical shape in a very short time. To stabilize the tape roll and avoid tape roll deformation, a round disk with the same diameter of the fresh tape roll has to be installed under the tape roll to provide support. However, since the disk has to turn with the tape roll, it increases the inertia for high speed application. It is not ideal to have the edge of the tape rubbing the surface of the disk during tape dispensing which may cause tape breakage if there is relative movement between the disk and tape which must occur if the disk is fixed and may occur even when the disk is free to rotate.
One other disadvantage of using the conventional in-line tape applicator for horizontal taping is space utilization. The average height of a tape applicator main body is 8 inches, but an additional 17 inches must be provided to accommodate the tape roll and its mounting. A loaded tape applicator can be over 2 feet tall and when turned on its side for tape application to a vertical surface requires an addition lateral space thereby increasing the machine space requirements. The additional lateral space creates a significant ergonomic disadvantage for the operator in threading the tape from the tape roll including the cutting off of the end of the tape at the application roller, since the operator has to reach in to perform these operations and/or perform any further adjustments often needed during the taping operation. See for example U.S. Pat. No. 5,025,608 issued Jun. 23, 1991 to Marchetti.
Chinese patent 201210125353.5 shows a very complicated system for applying tapes to vertical surfaces of cartons. In this system the tape is mounted for rotation on a horizontal axis positioned in a separate station spaced from the applicator and is turned 90° i.e. the plane of the tape is turned from horizontal to vertical for application to the carton. The invention incorporates a tape splicing system to facilitate tape replenishment in operation but it is clear that the space requirements are significant.
It has been known for a long time to turn the plane of the tape through 90° as it is dispensed from a tape roll and passes to the point of tape application, see for example U.S. Pat. No. 2,147,738 issued Feb. 21, 1939 or U.S. Pat. No. 3,423,042 issued Jan. 21 1968 to Lipfert or U.S. Pat. No. 4,401,503 issued Aug. 30, 1983 to Hertel. The use of an adjustable angle plate or long roller which has to be adjusted properly to orient the tape to align with the application roller has limited effectiveness. Intermittent tape movement and uneven tape tension may cause the tape to shift and/or lose alignment. Tracking rollers with side flanges used to guide both edges of the tape, but these tracking (side guide) rollers are only be effective with rigid thick tape and are not effective with normal thin gauge adhesive tapes.
The present invention provides an effective system for taping vertical faces of cases to render such application practical while reducing space requirements necessitated by earlier vertical face taper applicators. The invention provides for precise tape tracking adjustment.